Hydraulic elevator



., (No Model.)

' T. W. HEERMANS. v HYDRAULIC ELEVATOR.

No. 551,755. Patented Dec. 24, 1895.

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(no Model.) v 2 SheetsSh'eet 2 T. W. HEBRM-ANS. HYDRAULIC ELEVATOR.

v Nb. 551,765. Patented Dec; 24,1895.

- ANDREW RGRMMM. WWQUI'IIQWASIIINGTOMDI.

UNITED STATES PATENT FFICE;

THADDEUS IV. I-IEERIWIANS, OF EVANSTON, ILLINOIS.

HYDRAULIC ELEVATOR.

SPECIFICATION forming part of Letters Patent No. 551 ,765, datedDecember 24, 1895.

Application filed July 19, 1895. Serial No. 555,525. (No model.)

To all whom it may concern.-

Be it known that I, THADDEUS W. HEER- MANS, a citizen of the UnitedStates, residing at Evanston, in the county of Cook and State ofIllinois, have invented a new and useful Improvement in HydraulicElevators, of which the following is a specification.

This invention relates to improvements in hydraulic elevators of thetype known as vertical machines.

The invention consists substantially in the construction set forth inthe subjoined specification, and more particularly pointed out in theclaims.

Like letters refer to the like parts in the several figures of thedrawings, in which- Figure 1 illustrates a vertical longitudinal sectionof the preferred form of the apparatus. Fig. 2 illustrates in sideelevation an outline of the improvement connected to a car or cage, andFig. 3 illustrates a vertical longitudinal section of a modified form ofthe apparatus.

The present invention does not embrace an entire elevator, but onlycertain improvements pertaining to the motor for operating the elevator.In this vertical type of machine it is customary to mount the cylinderupon a base or platform, and, accordingly, such base or platform isshown in the accompanying drawings, and is designated by the letter A.This base may be formed of a hollow casting, as shown in Fig. 1 of thedrawings, provided with suitable ports a b, communicating respectivelybelow and above, as indicated.

. Referring to Fig. 1 of the drawings, the port a communicates with alower cylinder D, and through'a pipe 0 with an upper cylinder E. Asupply-pipe O communicates with the circulating pipe 0 at any convenientpoint, and a valve B, of anywell-known construction, is provided for thepurpose of putting the pipe 0 and the cylinder D in commu- The othercylinder E is secured at its upper and lower ends respectively to headsI and K, and between the heads II and I it is preferred to employstuffing-boxes L, of a wellknown construction, so as to make awatertight joint between these heads and the lower piston F, whichpasses through the same. A stuffing-box may also be provided at thepoint where the upper part or stem of the piston G passes through thehead. In this improvement the piston of the motor must be constructed soas to provide difierent areas for the water-pressure to act upon atdifferent points. It is manifest that these different areas may besecured by a variety of constructions, and in the present drawings thereare shown two forms of such construction.

area of the surface presented to the waterpressure is twice as greatwith the lower member as with the arrangement presented by theconnection of the upper member to such lower member of the interposedcoupling.

' Instead of having the piston composed of two members connected to eachother,directly or indirectly, and arranged in two independent cylinders,it is manifest that two cylinders maybe connectedso as to form one andthe two members of the piston joined, which modified construction isillustrated in Fig. 3 of the drawings. In this figure of the drawings, Adesignates the base, D the cylinder and F and G, respectively, the lowerand upper sides of the piston, which are arranged to present differentareas of surface to the water-pressure by reason of the fact that theupper side of the piston is connected to a large stem, which occupiesabout half of its area, and thusproportionately reduces its effectivesurface. The circulating-pipe O and supplypipe 0 and the valve B and thesmall pipes b and a are arranged in this figure in a similar manner tothat in which they are arranged in Fig. 1 of the drawings.

In. Fig. 2 of the drawings an outline of the improvement is shown asapplied to operating an elevator-eage lll, which cage may be connectedto a sheave N, secured to the top of the piston or piston-rod by a cable0, attached to the top of the cage and passing over one or morestationary sheaves arranged at the top of. the elevator-well, under thesheave or sheaves secured to the piston-rod, and up through an eyeboltor other suitable fastenin g device at the top of thewell. Acounterweight P is preferably employed to counterbalance the weight ofthe cage without the load, and may be connected to the top of the cageby a cable R, passing over one or more sheaves and down through thecage.

The operation of the improvement may be described as follows: To liftthe cage or car with its load the valve is shifted so as to allow thewater to be discharged or exhausted from underneath the piston andsupplied above the same, whereby said piston is depressed and the cageor car lifted. Then, to reverse the movement of the car, the valve isshifted, so as to allow the supply to pass through the pipes C C and l)a below the piston, or to the point where there is the greatest area ofpressure-surface, and thereby produce at that point a pressure which isabout twice as great as the pressure above, and consequently willovercome the pressure above and also the weight of the piston and itsconnections, and thus allow the car or cage to descend. In thus liftingthe piston power is stored by reason of the fact that it is in avertical position, and its weight, which has been lifted, remainssuspended upon the column of water 3 but when such water-pressure isremoved from underneath the piston it will descend by gravity and thusexert the power stored in lifting the same, and in descending itsgravity will assist in lifting the load. It will thus be seen thatinasmuch as there is a constant supply of water to the smaller or up perarea of piston-surface the pressure will be upon it all the time; butwhen the waterpressure is admitted to the larger area of piston-surfacethe effect will be that this greater area of pressure-surface will givegreater power and overcome the water-pressure upon the smaller area, andtherefore lift the piston and allow the car or cage to descend, and atthe same time store up just as much energy as was required to lift theweight of the piston, so that when the water-pressure is no longerexerted-upon the larger area of the piston and the discharge therefromis open there will be available for lifting the load not only thewater-pressure upon the smaller area of the piston, but also the weightof the piston and connections, from which it follows that there is auniform demand on the pumping plant, and that a smaller pump than isusual is required and a more constant service. The demand 011 thepumping plant may be stated as follows, to wit: The waterpressure mustbe sufficient when acting on the smaller area of piston-surface to liftthe load minus the weight of the piston and connections, or, in otherwords, the water-pressure plus the weight of the piston and connectionsis sufficient to overcome the load, and, therefore, the cage with itsload will descend whenever there is sufficient power applied to lift theweight of the piston and connections. To state it differently, thewaterpressure as supplied from the pumping plant must be suflicient toovercome the weight of the equivalent of just one'half of the maximumload, whether the car is going up or down, and the power required to beexerted is given us by the difference in surface area presented by thepiston at different times to the water-pressure, and there is notcreated any different demand on the pumping plant. It is, of course, tobe understood that it is preferable that the weight of the cage andcables is to be counterbalanced in the usual manner,as heretoforedescribed, and as shown in Fig. 2 of the drawings.

It is obvious that manymodifications may be made in the details of theconstruction without departing from the principle of the invention.

\Vhat I claim, and desire to secure by Letters Patent of the UnitedStates, is

1. In a hydraulic elevator, a piston, having two distinct areas ofpressure surface, the lower one of which is twice as great as the other,in combination with pipes forming a communication between the watersupply and the two distinct areas of pressure surface mentioned;substantially as and for the purpose set forth.

2. I11 a hydraulic elevator, a piston, of approximately the weight ofhalf the maximum load, and having two distinct areas of pressuresurface, the lower surface being twice as great in area as the other,and suitable pipe communications between the water power and thesedifferent areas of piston; substantially as and for the purpose setforth.

3. In a hydraulic elevator of the vertical machine type, the combinationwith an upper cylinder and a lower cylinder, of a piston composed of twomembers having respectively different areas of pressure surface, thesmaller being placed in the upper and the larger in the lower cylinder,a cire ulating pipe between the two cylinders and having freecommunication with the upper cylinder, and a valve between suchcirculating pipe and the lower cylinder for controlling the supply anddischarge to and from the same; sub-- stantially as and for the purposeset forth.

In witness whereof I have hereunto set my hand this 17th day of July,1895.

THADDEUS \V. IIEERMANS.

Attest:

FRANK T. BROWN, M. I. CAVANAGH.

